Certain sustained release technology suitable for administration by inhalation employs lipid based formulations such as liposomes to provide prolonged therapeutic effect of drug in the lung and systemically by sustained release and the ability to target and enhance the uptake of drug into sites of disease.
For a lipid based drug delivery system, it is often desirable to lower the lipid-to-drug (L/D) ratio as much as possible to minimize the lipid load to avoid saturation effects in the body. For lung delivery by inhalation, this may be particularly true because for chronic use, dosing of lipid could outpace clearance thus limiting the administration and thus effectiveness of the drug product. A lower L/D ratio would allow more drug to be given before the dosing/clearance threshold is met.